This invention is directed to novel organosulfur adducts of propylene based lube olefins as unique multifunctional additives as well as multifunctional lubricants with inherent multifaceted internal synergism.
Lubricants, such as lubricating oils and greases, are subject to oxidative deterioration at elevated temperatures or upon prolonged exposure to the elements. Such deterioration is evidenced, in many instances, by an increase in acidity and in viscosity, and when the deterioration is severe enough, it can cause metal parts to corrode. Additionally, sever oxidation leads to a loss of lubrication properties, and in especially severe cases this may cause complete breakdown of the device being lubricated. Many additives have been tried, however, many of them are only marginally effective except at high concentrations. Improved antioxidants are clearly needed.
Antioxidants or oxidation inhibitors are used to minimize the effect of oil deterioration that occur when hot oil is contacted with air. The degree and rate of oxidation will depend on temperature, air and oil flow rates and, of particular importance, on the presence of metals that may catalytically promote oxidation. Antioxidants generally function by prevention of chain peroxide reaction and/or metal catalyst deactivation. They prevent the formation of acid sludges, darkening of the oil and increases in viscosity due to the formation of polymeric materials.
Additionally lubricants are under heavy distress that can affect their antiwear and load carrying ability particularly between steel on steel moving surfaces. Sulfurized olefins have been well known for their extreme pressure and antiwear properties when formulated into lubricants and fuels as noted by U.S. Pat. No. 3,703,50, and references contained within.
The use of phosphorodithioates, especially salts of phosphorodithioates, such as zinc dialkylphosphorodithioates (commonly known as zinc dithiophosphates) have found widespread commercial use for several decades in engine oils as multifunctional antiwear, peroxide decomposing, and bearing corrosion inhibiting additives.
Replacement of zinc dithiophosphates by zinc/phosphorus-free antiwear additives in hydraulic fluids, gear oils and various other lubricating systems is highly desirable because of environmental considerations. In addition, a sulfur-containing additive which overcomes the problems of odor, staining and volatility is also highly desirable. Finally, an additive system or fluid which exhibits antiwear activity in combination with antioxidant activity and copper passivation is highly desirous. Thus, it is an object of this application to generate compositions that when used either as a fluid media or additive imparts enhanced oxidative stability, reduced wear, increased load carrying capabilities and improved rust inhibition.